package ooday04;

import javax.naming.NameNotFoundException;

/** 多态的演示 */
public class PolymorphicDemo {
    public static void main(String[] args) {
        //演示向上造型:
        /*
        Dog o1 = new Dog("小黑",2,"黑");    //狗是狗
        //o1.name/age/color/drink()/eat()/swim()/lookHome();
        Animal o2 = new Dog("小黑",2,"黑"); //狗是动物---向上造型
        //o2.name/age/color/drink()/eat();
        Swim o3 = new Dog("小黑",2,"黑");   //狗会游泳---向上造型
        //o3.swim();
         */

        //演示强转成功的条件:
        /*
        Animal o = new Dog("小黑",2,"黑");
        Dog g = (Dog)o; //引用o所指向的对象，就是Dog类型
        Swim s = (Swim)o; //引用o所指向的对象，实现了Swim接口
        //Fish f = (Fish)o; //运行时会发生ClassCastException类型转换异常

        System.out.println(o instanceof Dog);  //true
        System.out.println(o instanceof Swim); //true
        System.out.println(o instanceof Fish); //false
        if(o instanceof Fish){ //false
            Fish f = (Fish)o;
        }
        */

        //演示向上造型(多态)的第1点应用:
        /*
        Master master = new Master();
        Dog dog = new Dog("小黑",2,"黑");
        Chick chick = new Chick("小花",3,"花");
        Fish fish = new Fish("小金",1,"金");
        master.feed(dog); //在传参的同时，系统自动做了向上造型
        master.feed(chick);
        master.feed(fish);
         */

        //演示向上造型(多态)的第2点应用:
        //Animal o = new Animal(); //编译错误，抽象类不能被实例化
        Animal[] animals = new Animal[5];
        animals[0] = new Dog("小黑",2,"黑"); //向上造型
        animals[1] = new Dog("小白",1,"白");
        animals[2] = new Fish("小金",1,"金");
        animals[3] = new Fish("小花",2,"花");
        animals[4] = new Chick("小灰",3,"灰");
        for(int i=0;i<animals.length;i++){ //遍历所有动物
            System.out.println(animals[i].name); //输出每个动物的名字
            animals[i].drink(); //每个动物喝水
            animals[i].eat(); //每个动物吃饭

            if(animals[i] instanceof Dog){
                Dog dog = (Dog)animals[i];
                dog.lookHome();
            }
            if(animals[i] instanceof Chick){
                Chick chick = (Chick)animals[i];
                chick.layEggs();
            }
            if(animals[i] instanceof Swim){ //适用于所有实现Swim接口的(会游泳的)
                Swim s = (Swim)animals[i];
                s.swim();
            }

        }
    }
}

















